In recent years, organic light-emitting devices such as organic electroluminescence (EL) panels and organic EL lighting have been actively developed.
An organic EL panel has a configuration in which sub-pixels are arranged in two dimensions on a surface of a substrate. Each sub-pixel has a layered configuration in which an anode, a hole injection layer (HIL), a hole transport layer, an organic light-emitting layer, an electron transport layer, and a cathode are layered in this order on the substrate. The hole injection layer, hole transport layer, and electron transport layer have a function of injecting a charge (electrons, holes) from the anode or cathode to the organic light-emitting layer or a function of transporting a charge from the anode or cathode to the organic light-emitting layer, and therefore these layers are referred to as charge injection/transport layers.
Here, as an electron transport layer, the use of an organic material layer doped with barium, for example, has been studied and developed. By using such an electron transport layer, high electron injectability can be achieved.
Further, in view of the problem of degradation of a charge injection/transport layer easily occurring due to impurities (moisture and oxygen), Patent Literature 1 discloses a configuration in which a barrier layer formed from an inorganic material is disposed between the organic light-emitting layer and the electron transport layer. As an inorganic material disclosed in Patent Literature 1, an example is silicon oxide (SiOx).